It is known to provide shelf lifting or counterbalance mechanisms of the type including a frame for mounting a shelf support for vertical movement under the control or influence of a spring device coupled to the shelf support by a cable system. Prior patents disclosing this type of mechanism includes U.S. Pat. Nos. 2,604,996; 2,932,403; 3,436,136; 3,807,821; 3,820,478; 3,871,725; 4,009,915; 4,559,879; 4,605,189; 4,828,119; 4,898,103. Of these patents, U.S. Pat. No. 3,807,821 proposes the use of a lever assembly for connecting a spring to a cable system in such a manner that the extent of travel of shelf support exceeds the extent of travel of the spring.